Electrospinning of Aqueous Solutions of a Triethylammonium Salt of Polyamic Acid and Properties of the Nonwoven Polyimide Materials

Abstract

The electrospinning conditions of aqueous and aqueous-alcoholic solutions of the triethylammonium salt of a polyamic acid derived from pyromellitic dianhydride and 4,4′-diaminodiphenyl ether in the concentration interval 8–15 wt % were studied comprehensively. The best operation characteristics of the nonwoven materials are reached when forming the fibers from a 10% solution of the prepolymer in a 70/30 wt % alcohol/water mixture at the reaction mixture viscosity in the interval 0.27–0.96 Pa s and the surface tension of 26 mN m−1. The dynamics of thermal imidization of the nonwoven material based on the triethylammonium salt polyamic acid was monitored by IR spectroscopy; it was found that the imide ring formation was complete at 200°C. Samples of the nonwoven polyimide material were obtained, and their deformation, strength, and thermal properties were determined.